US2630267A

US2630267A - Radial flow fan

Info

Publication number: US2630267A
Application number: US225207A
Authority: US
Inventors: Allen G Ostrognai
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1951-05-08
Filing date: 1951-05-08
Publication date: 1953-03-03
Anticipated expiration: 1970-03-03

Description

March 3, 1953 A. G. OSTROGNAI 2,630,267

RADIAL FLOW FAN Filed May 8, 1951 2 SI-IEETSSHEET 1 FLQI. 29

Inventor: Allen 6. Ostflgnai, y 6% I His Attorney.

March 3, 1953 A. G. OSTRQGNAI 2,630,267

RADIAL FLOW FAN Filed May 8, 1951 2 sHEETssl-lEET 2' 700- E g 600- E 5500 E $400-- X 300 E 100- E g 10/ 0 I 2 3 4- 5 6 7 8 9 IO U l2 l3 l4 [5 I6 RADIAL p/sm/vcE (FEET) E i g 1 I k1 I 5, 3 I 1 1 1 E l \I /I m E I 32 v I l l6 l4 l2 l0 6 4 Z 0 a RADIAL DISTANCE (FEET) His Attorney.

Patented Mar. 3, 1953 RADIAL FLOW FAN Allen G. Ostrognai, Milford, Conn assignor to General Electric Company, a corporation of New York Application May 3, 1951, Serial No. 225,207

9 Claims.

This invention relates to rotary-driven, airmoving fans and more particularly to such fans in which the air is discharged radially with respect to the rotating members.

Radial flow fans are particularly suited to be used as floor-type fans, since if a radial flow fan is mounted with its rotating shaft extending vertically with respect to the floor, it tends to produce air streams flowing in all directions along the floor. These air stream will in turn cause a rolling circulation of the air lyin above them and thus produce a ventilating effect throughout the room in which the fan is positioned. Naturally, the stronger the floor air streams, the better will be over-all ventilation of the room.

It is a general object of this invention, therefore, to provide a new and improved radial flow fan which, for a given power input, will produce stronger radial air streams than those fans heretofore available; and it is a more specific object of the invention to provide a new and improved radial flow fan particularly adapted for use as a floor-type fan.

In accordance with the foregoing objectives, there is provided a fan having a vertically disposed shaft on which two sets of fan blades are mounted in spaced vertical relationship. The lower set of blades discharges air upwardly along the shaft while the upper set of blades discharges air downwardly along the shaft. These air streams oppose each other so that they both tend to combine and discharge outwardly from the shaft in the space lying between the two sets of blades. This radial discharge effect may be aided by positionin special orifice members around each of the sets of blades to aid in shaping their discharge patterns, and also by constructing one set of blades with a blade surface curvature in reverse to the normal curvature for its direction of axial discharge. In order to confine the radial discharge of the combined air streams to a particularly desirous vertical angle, a plurality or" vertically spaced annular louvers are employed. These louvers are positioned so that the air in flowing outwardly passes between them and is guided thereby to the correct angle. Not only does this fan produce a stronger radial air stream than conventional floor-type fans of the same size, but it also obtains a better rolling circulation of the room air for a given output air stream because it takes its suction on both sides of the output air stream, 1. e., it sucks in air at it top for one set of blades and at its bottom for the other set of blades.

The features of this invention, which are believed to be novel, are set forth with particularity in the appended claims. The invention itself, however, both as to organization and mode of operation, together with further objects and advantages thereof, may be best understood by reference to the following description, to be taken in conjunction with the accompanying drawing in which:

Fig. 1 is a front elevation view, partially in section, of a floor-type fan embodying this invention;

Fig. 2 is a performance curve for a given size fan similar in construction to that illustrated in Fig. 1, showing the maximum velocity of the radial air stream produced by the fan versus radial distance from the fan; and

Fig. 3 is another performance diagram for the same fan as the curve of Fig. 2, showing the height of the radial air stream above the floor versus radial distance from the fan.

Referring to Fig. l, the base i of a floor-type fan embodying this invention includes 'a disk-like motor mounting plate 2, three supporting leg 3 which extend outwardly from the plate, and an annular rim member 5 which joins together the outer ends of legs 3. In order to vibration-insulate the fan from the floor, a resilient foot 5, preferably formed of rubber, is mounted under each of legs 3 by a screw 6. The fan drive motor l is secured to the base by a support bracket 8 and a plurality of screws 9, and its shaft It extends vertically upward away from the base. As shown, shaft It need not be one piece, but may consist of an extension shaft Ida coupled to the actual motor drive shaft Hlb.

Mounted in spaced vertical relationship on shaft 55 are two sets of essentially axial flow fan blades H and I2. The lower set of blades H discharges air upwardly along shaft It while the upper set of blades l2 discharges air downwardly along shaft it. These streams of air thus oppose each other in the space lying between the two sets of blades and tend to discharge radially out- Ward from shaft ill.

The fan housing which encloses the motor and the fan blades includes means which aid in forming this radial air discharge. The lower portion of the fan housing comprises a cage formed of a plurality of vertically spaced rings I3 which are secured on supporting struts M by welding or other suitable means, the struts themselves bein mounted on base by bolts l5. Besides the actual supporting struts i i, additional struts It are secured to rings i3 so as to stiffen the cage. This lower cage portion extends upwardly from rim 4 to a point slightly below the neutral plane of blades II. In other words, the cage encloses the lower portion of blades I I but not their upper portion, and it is through the opening between the ca e rings that blades H take the major portion of their suction.

Struts I4 and I6 extend upwardly slightly beyond the uppermost ring I3 and have horivontal loops II formed at their upper extremities. It is on these loops that the aforementioned airdirerting means are mounted. Thus, positioned directly above loops I! is an annular orifice member I8 while mounted on top of member I8 are a plurality of annular louvers I9. Orifice member I8 is provided with a number of spacing bosses or pro ections 20, and louvers I9 are provided w th similar bosses 2|. Bosses and 2I each contain a vertically extending hole or aperture through which extends a retaining bolt 22, the bosses thereby serving not onlv to space orifice member I8 and louvers I8 vertically from each other but also to secure them firmly in place. In order to reduce the r resistance to air flow,

bosses

20 and 2| should preferably have either a parallel-sided oval or a tear-drop shaped cross sectional area.

Orifice member I8, in effect, forms an air passagewav which encloses most of the upper portion of blades II and is tapered from its bottom to its too. In other words, the horivontal diameter of the passageway decreases with vertical distance from base I. This tapered passageway of member I8 aids in shaping the discharge from blades I I into an axial flow moving upwardly along shaft III.

Louvers I9 are spaced vertically from the upper edge of orifice member I8 to a point near the lower edges of blades I2. The louvers thus enclose the space in which the separate air streams from blades II and I2 interact and combine to form one radially moving air stream. To obta n the best circulation of room air, it is desirable that this output air stream be directed slightly upwardly as it leaves the fan, as will be more fully explained hereinafter, and to accomplish that result louvers I9 are constructed so that their upper and lower surfaces form acute angles with their horizontal transverse diameters. Naturally, it is important that the louvers present as little resistance as possible to the air flow and for that purpose they are preferably formed with a parallel-sided oval or tear-drop shaped cross section.

Mounted above the uppermost louver on each of the bolts 22 are spac ng

members

23, 24 and 25 which are substantially identical in shape, each being of a parallel-sided oval cross section and each having a small recess formed in the lower portion of its outer edge. In the case of

members

24 and 25 these recesses are used to mount protective or safety rings 26 and 21, ring 28 being mounted in the recesses of members 24 and ring 21 being mounted in the recesses of members 25. Ring 26 is, however, close enough to the outer edge of the uppermost louver that no protective ring need be mounted in the recesses of members 23. Besides mounting protective rings 26 and 21, spacing

members

24 and 25 also serve to hold in place an orifice member 28, the lower edge of member 28 being secured between

members

24 and 25. From its lower edge which thus lies approximately at the neutral plane of blades I2, member 28 extends upwardly to a point slightly above the upper edges of the blades and thereby forms an air passageway enclosing the upper portion of the blades. The passageway is tapered from top to bottom so that its horizontal diameter decreases with vertical distance from base I, and this taper helps to produce the desired flow pattern for the air stream leaving blades I2.

Positioned over orifice member 28 is a grill cover 29 which has a solid rim 3!) resting directly on members 25. Bolts 22 are threaded into tapped apertures formed in rim 30 so as to secure in place the entire upper portion of the fan housing. As its name indicates, grill cover 30 is provided with numerous openings, and it is through those openings that blades I2 take their suction.

The speed at which the fan blades rotate and thus, the strength of the output air stream of the fan may be varied by means of a multi-position switch 3| which is connected in the drive motor circuit. Switch 3| has an off position and a plurality of on positions whereby the motor may be made to rotate at various speeds.

As previously mentioned, orifice members I8 and 28 are included in the fan structure so as to aid in producing such discharge patterns in the opposing axially flowing air streams that they will combine efficiently to produce one radially flowing air stream. These discharge patterns are also, of course, dependent upon both the pitch and the surface curvatures of blades II and I2. Thus, viewing the fan from its top end and assuming its direction of rotation to be clockwise as so viewed, the leading or air-impelling surfaces of blades II extend rearwardly and upwardly from their leading edges to their trailing edges so that they will propel air upwardly, while the leading or air-impelling surfaces of blades I2 extend rearwardly and downwardly from their leading edges to their trailing edges so that they will propel air downwardly. The air-impelling surfaces of blades II are provided with the normal surface curvature for axial flow fan blades being concave in the direction of air flow from their leading to trailing edges, i. e., being concave in the direction of blades I2; but, in accordance with this invention, the air-impelling surfaces of blades I2 are provided with a curvature in reverse to the normal curvature for axial flow fan blades, being convex in the direction of air flow from their leading to their trailing edges, i. e., being convex in the direction of blades II. By forming blades I 2 with this reverse curvature. appreciably better results are obtained from the fan as a whole.

The reverse curvature of blades I2 causes the air stream leaving them to diverge outwardly as it moves down shaft Ill. The shape of orifice member 28 also aids in causing the discharge of blades I2 to have radial as well as axial components of direction. The normal curvature of blades I 5, however, together with the shape of orifice It causes the air leaving blades II to have substantially only axial components. The result of the downwardly moving stream having radial as well as axial components of direction and the upwardly moving stream having only axial components is that when the two streams of air meet in the space enclosed by the louvers, they combine with a minimum of turbulence into a stream of air moving substantially radially but also moving somewhat upwardly. The combined air stream is then able to pass between louvers I9 with a minimum of contact, and thus, a minimum loss of speed due to any surface drag of the louvers.

This feature of the invention should not, however, be construed as limited to a fan in which th upper setor blades is provided -virith 'a revers surface curvature and the ltiwer set of blades is provided with a normal surface curvature. Equally-gees results may be obtained by providin the lower set of blades with the reverse surface curvature and the upper set of blades with the normal surface curvature. Inthis case,

lower blades would be convex from their leading to trailing edges in the direction of the upper blades, While the upper blades would be concave from their leading to trailing edges in the direcnon 'of th rower blades. g

if neither Set of blades has a reverse curvature, the opposing streams of air still combine into one radially moving stream but the turbulent eifectis much greater so that the efflci'e'ncy of the fan is lowered. Louver s iii, of sense, insure that the combined air stream leaves the fan at the correct angle even if both sets of blades have a normal surface curvature. In any case, no matter what the surface curvature of the Hades may be, an upward as well as an outward movement of the combined air stream into the Ilouvers may be accomplished by making the lower blades more powerful than the upper blades.

The reason why the discharge of the fan should have upward as well as radial components of di- .rection may be understood by reference to the air stream lines shown in Fig. 3, whichare for a fan of the type shown in Fig. l standing approximately inches high and having an outer housing diameter of approximately 16% inches at its widest point. Such a fan draws about as watts power input when creating its maximum velocity output air stream. As the air stream leaves the fan, as indicated by

stream lines

32, 33 and 3 1, it creates beneath it a low pressure area so that it tends to dip toward the floor. By directing the air stream slightly upwardly as it leaves the fan, the dip is made to occur at a point more distant from the fan than that point at which it would occur if the air stream were directed outwardly from the fan in a horizontal plane. The more remote point of dip is desirable, since if the dip occurs too close to the fan, a large portion of the output air stream is drawn right back into the lower fan blades. The dip itself is desirable because it causes the output air stream to form a jet along the floor.

As the air stream flows along the floor, it picks up and accelerates the air adjacent to its flow path so that a rolling action of the air occurs in the space above the how path. This rolling aetion causes a circulation of air which is indicated by the dotted lines in Fig. 3 and tends to ventilate the entire room in which the fan pesitioned. The maximum velocity of the output air stream, which occurs approximately along stream line 2, is plotted in Fig. 2. For example, at about 1 /2 feet from the fan the maximum velocity of the air stream is 950 feet per minute, while at 15 feet it is approximately '60 feet per minute. This means that even at a distance of 15 feet from the fan, there is an appreciable ventilating eifect.

Besides the improved jet action of its output air stream, the fan also has another important advantage in that it delivers a larger volume of air at a greater velocity than do conventional floor-type fans of similar size. Naturally, the greater the volume of air flow, the better ventilating effect is obtained in the room. Moreover, the rolling circulation of the air and, thus, the ventilating efiect is augmented by the fan taking a portion of its suction from above the output air stream. Of course, as a result of part of the air entering the top of the fan, less air need be drawn in at the bottom of the fan so that the velocity 'of the air entering the bottom for a given output air new is less than in most conventional fans. This decreases the likelihood of lint, dust, ashes, etc., being drawn into the fan by the return air so as to be dispersed throughout the room; Thus, even though the fan produces an increased velocity, jet action output for a better ventilating effect, it has little tendency to introduce foreign matter such as dust into the air stream.

While there has been described what at present is considered to be the preferred embodiment of this invention, it will be obvious to those skilled in the art that numerous alterations and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such alterations and modifications as fall within the true spirit and scope of this invention.

What -I claim as new and desire to secure by Letters Patent of the United States is:

1. A fan including a supporting base, a motor mounted on said base having a vertically extending shaft, a first fan blade mounted on said shaft for discharging a stream of air upwardly along said shaft, a second fan blade mounted on said shaft above said first blade for discharging a stream of air downwardly along said shaft, one of said blades having a surface curvature from its leading to its trailing edge convex in the direction of the other of said blades and said other blade having a surface curvature from its leading to its trailing edge concave in the direction of said one blade whereby said air streams are shaped to combine and discharge radially from said shaft upon their meeting in the space between said blades.

2. A fan including a supporting base, a motor mounted on said base having a vertically extending shaft, a first set of fan blades mounted on said shaft for discharging a stream of air upwardly along said shaft, a second set of fan blades mounted on said shaft above said first set of fan blades for discharging a stream of air downwardly along said shaft to meet said upwardly discharged stream, the blades of said first set having a surface curvature from their leading to their trailing edges concave in the direction of said second set and the blades of said second set having a surface curvature from their leading to their trailing edges convex in the direction of said first set to cause said streams of air to combine and discharge outwardly from the space between said sets of blades.

3. A fan comprising a supporting base, a motor mounted on said base having a vertically extending' shaft, a pair of orifice members mounted on said base in spaced vertical relationship, each of said members having a vertically extending tapered passageway enclosing said shaft, both of said passageways being tapered to have an increasing horizontal diameter in the same verticaldirection, a first fan blade mounted on said shaft in one of said passageways for discharging a stream of air upwardly along said shaft, and a second fan blade mounted on said shaft above said first fan blade in the other of said passageways for discharging a stream of air downwardly along said shaft to strike said upwardly discharged stream in the space between said orifice members, the taper of said passageways aiding in shaping said streams of air to cause them to com- 7 bine and discharge radially from the shaft in the space between said orifice members.

4. A floor-type fan including a supporting base, a motor mounted on said base having a vertically extending shaft, a pair of vertically spaced orifice members mounted on said base, each of said members having a vertically extending tapered passageway enclosing said shaft, a first fan blade mounted on said shaft in one of said passageways for discharging a stream of air upwardly along said shaft, a second fan blade mounted on said shaft above said first fan blade in the other of said passageways for discharging a stream of air downwardly along said shaft to meet said upwardly discharged stream, one of said blades having a surface curvature from its leading to its trailing edge convex in the direcion of the other of said blades and said other blade having a surface curvature from its leading to its trailing edge concave in the direction of said one blade, whereby said passageway and said blades coact to shape said streams of air to effect a combined radial discharge thereof upon their meeting in the space between said blades.

5. A fan including a supporting base, a motor mounted on said base having a vertically extending shaft, a first fan blade mounted on said shaft for discharging a stream of air upwardly along said shaft, a second fan blade mounted on said shaft above said first blade for discharging a stream of air downwardly along said shaft to meet said upwardly discharged stream, one of said blades having a surface curvature from its leading to its trailing edge convex in the direction of the other of said blades and said other blade having a surface curvature from its leading to its trailing edge concave in the direction of said one blade, and a plurality of annular louvers mounted on said base and disposed around said shaft and blades in an area horizontally opposite the space between said blades for directing said streams of air away from said shaft upon their meeting in the space between said blades.

6. A floor-type fan including a supporting base, a motor mounted on said base having a vertically extending shaft, a pair of orifice members mounted on said base in spaced vertical relationship, each of said members having a vertically extending tapered passageway enclosing said shaft, both of said passageways being tapered to have an increasing horizontal diameter in the same vertical direction, a first fan blade mounted on said shaft in one of said passageways for discharging a stream of air upwardly along said shaft, a second fan blade mounted on said shaft above said first fan blade in the other of said passageways for discharging a stream of air downwardly along said shaft to meet said upwardly discharged stream, the taper of said passageways aiding in shaping said streams of air to cause them to combine and discharge radially from the shaft in the space between said orifice members, and a plurality of annular louvers secured between said orifice members for directing said streams of air outwardly at a predetermined angle.

7. A fan comprising a supporting base, a motor mounted on said base havin a vertically extending shaft, a pair of orifice members mounted on said base in spaced vertical relationship, each of said members having a vertically extending passageway enclosing said shaft, both of said passageways being tapered to have an increasing horizontal diameter in the same vertical direction, a first fan blade mounted on said shaft in one of said passageways for discharging a stream of air upwardly along said shaft and a second fan blade mounted on said shaft in the other of said passageways above said first blade for discharging a stream of air downwardly along said shaft to strike said upwardly moving stream, one of said blades having a surface curvature from its leading to its trailing edge convex in the direction of the other of said blades and said other blade having a surface curvature from its leading to its trailing edge concave in the direction of said one blade, the curvature of said blades and the taper of said passageways shaping said streams of air to cause them to combine and discharge radially from the shaft in the space between said orifice members, and a plurality of annular louvers secured between said orifice members for directing said streams of air outwardly at a predetermined angle.

8. A floor type fan including a supporting base, a motor mounted on said base having a vertically extending shaft, a pair of vertically spaced orifice members mounted on said base, each of said members having a vertically extending tapered passageway enclosing said shaft, a first fan blade mounted on said shaft in one of said passageways for discharging a stream of air upwardly along said shaft, and a second fan blade mounted on said shaft above said first fan blade in the other of said passageways for discharging a stream of air downwardly along said shaft to strike said upwardly discharged stream in the space between said orifice members, the taper of said passageways aiding in shaping said streams of air to cause them to combine and discharge radially from the shaft in the space between said orifice members.

9. A fioor type fan including a supporting base, a motor mounted on said base having a vertically extending shaft, a first fan blade mounted on said shaft near the bottom thereof for discharging a stream of air upwardly along said shaft, a second fan blade mounted on said shaft near the top thereof and spaced above said first fan blade for discharging a stream of air downwardly along said shaft to meet said upwardly discharged stream, and a plurality of annular louvers mounted on said base and disposed around said shaft and blades in an area horizontally opposite the space between said blades for directing said streams of air away from said shaft and outwardly at a predetermined angle upon their meeting in the space between said blades.

ALLEN G. OSTROGNAI.

No references cited.